Avoids NullPointerException when no config nor credentials files are found in ~/.aws/ and ProfileFile.profiles() method is called (#3942)

Co-authored-by: Matthew Miller <[email protected]>

Author: martinKindall

.changes/next-release/bugfix-AWSSDKforJavav2-540f927.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "martinKindall", 
+    "type": "bugfix", 
+    "description": "Avoids NullPointerException when config and credentials files were not found for profiles. Now it returns an empty map, as it used to."
+}

core/profiles/src/main/java/software/amazon/awssdk/profiles/ProfileFile.java

@@ -117,7 +117,7 @@ public Optional<Profile> profile(String profileName) {
      */
     public Map<String, Profile> profiles() {
         Map<String, Profile> profileMap = profilesAndSectionsMap.get(PROFILES_SECTION_TITLE);
-        return profileMap != null ? Collections.unmodifiableMap(profileMap) : profileMap;
+        return profileMap != null ? Collections.unmodifiableMap(profileMap) : Collections.emptyMap();
     }
 
     @Override

core/profiles/src/test/java/software/amazon/awssdk/profiles/ProfileFileTest.java

@@ -554,6 +554,15 @@ public void loadingDefaultProfileFileWorks() {
         ProfileFile.defaultProfileFile();
     }
 
+    @Test
+    public void returnsEmptyMap_when_AwsFilesDoNotExist() {
+        ProfileFile missingProfile = ProfileFile.aggregator()
+                                                .build();
+
+        assertThat(missingProfile.profiles()).isEmpty();
+        assertThat(missingProfile.profiles()).isInstanceOf(Map.class);
+    }
+
     private ProfileFile configFile(String configFile) {
         return ProfileFile.builder()
                           .content(new StringInputStream(configFile))